Vacuum distillation process and apparatus



VACUUM DISTILLA'IION PROCESS AND APPARATUS Filed June 27, 1946 a Shams-Sheet 1 ALBERT 6. [1055/5 INVENTOR ATTORNEY w B 0 H a A VACUUM DISTILLATION PROCESS AND APPARATUS Filed June 27, 1945 2 Shams-Sheet 2 461345397 6. HOBBIZ' INVENT OR ATTORNEY as TE'l oer-ice VADIS TION PROCESS APPARATUS Albert i7. obbic, Moorcstown, N. 3., ignor to motion Products,

Inc, Rochester, N. Y., a

corporation of Delaware Application June 27, l9d6, Serial No. 679,163

This invention relates to improved vacuum distillation process and apparatus and, in particular, to an improved self-evacuating centrifugal vacuum still.

In Hickman Patents 2,210,927-8, August 13, 1940, there is described improved vacuum distillation process and apparatus wherein the substance to be distilled is caused to flow over a vaporizing surface by centrifugal force. the material being distilled being heated to distillation temperature and hot undistilled residue being removed from the still without utilization of the heat content thereof.

This invention has for its object to pnovide an improved centrifugal vacuum distillation process and apparatus wherein the heat content of the und-istilled residue is utilized to vaporize the actuatlng fiuid in a condensation pump operated to evacuate the still. Another object is to markedly reduce the heat losses which have heretofore been inherent in processes of high vacuum unobstructed path distillation. Other objects will appear hereinafter.

These and other objects are accomplished by my invention which includes high vacuum centrifugal distillation process and apparatus wherein dlstilland is introduced onto a rotatable vaporizing surface, is caused to how by centrifugal force to the periphery of said surface and is then quickly brought in heated condition into heat exchange contact with a boiler of a condensation pump containing vaporizabie pump fluid which boiler is '1 Claims. (or. 202-52) positioned adjacent the periphery of said surface.

In the following description I have given severa] of the preferred embodiments of my invention but it is to be understood these are set forth for the purpose of illustration and not in limitation thereof.

In the accompanying drawings wherein like numbers refer to like parts, Fig. 1 is a. vertical section of an improved centrifugal vacuum still embodying the principles of my invention and Fig. 2 is a horizontal section taken on line 22 of Fig. 1.

Referring to the drawings, numeral 4 designates a conical still casing provided at the base with an integral base 6 and at the top with an integral annular gutter 8 the outer lip of which joins with annular plate It. Numeral l2 designates an annular groove at the periphery of plate I0 into which still cover I! fits in a gas-tight manner.

Numeral l8 designates a shaft mounted in the approximate center of base plate 6 and cover I! and which is rigidly maintained in this position by bearings l8 and 20. The lower portion of shaft ii is integral with a conical vaporizing surface 22 which is therefore rotatably mounted. Numeral 24 designates a driving pulley at the upper end of the shaft serving to rotate shaft l6 and integral vaporizing surface 22. The upper end of vapormed-lately below deflector 28. Numeral 65 indi 2 izing surface 22 is provided with an outwardly turned flange 2t and a collar 26 which protrudes into a stationary annular deflecting member 28. Numeral 32 designates a conduit for introducing distilland onto the inside central portion of conical vaporizing plate 22. Numeral 5 designates a heating element for heating vaporizing surface 22 to distillation temperature.

Numeral Bl designates a plurality of annular collars mounted inside vaporizing cone 22 which act as condensing surfaces. These collars are positioned so that liquid collecting on an upper collar drops onto the next lowest collar and eventually drains into an annular gutter 34. These condensing members 3i are cooled by integral cooling conduits 35 through which cooling fluid is circulated. Numeral 38 designates a stationary pump, the intake side of which is connected to conduit to leading to gutter 3tand the exhaust side of which pump is connected to conduit 42 leading to the outside of the still. Pump 38 is driven by gear M which meshes with gear 56, integral with shaft it.

Collar it is provided with a-number of circular holes 68 in which are mounted cone difiusing tubes at which are cooled with integral cooling coils 52 through which cooling fluid iscirculated.

Immediately below openings and integral with plate It is mounted an annular double walled element 54 having a cup shaped cross section to which is connected withdrawal conduits 56 leading to backing pumps (not shown). The lower portion of 515 is connected to a conduit 58 which leads to the intake of a plurality of withdrawal pumps 88, the exhaust sides of which are connected by conduits S2 to annular boiler 65 which surrounds the upper outer periphery of rotating vaporizing surface 22 and which is positioned imcates a low vapor pressure pump fluid contained in boiler 65 and in the lower portion of cups 54. Numeral 86 designates ejector nozzles positioned above each of the openings 18 in plate l0 and numeral 10 designates a conduit connecting boiler 54 to the elector nozzles.

In operating the apparatus illustrated in the drawings backing pumps (not shown) are com nected to cohduits 56 and the entire system is thus partially evacuated. Liquid to be distilled is then introduced through conduit 32 and vaporizing surface 22 is caused to rotate by force applied to pulley 2|. Heating element 5 is actuated to heat vaporizing surface 22 to distillation temperature. The introduced'distilland is caused to flow in a thin film by centrifugal force up the inside wall of cone 22. During passage vapors are generated and condense on cooling collars 3 l.

The liquid condensate drains into gutter 3, is withdrawn therefrom through conduit ill by pump 3! an is delivered from the still through conduit l2. Hot undistilled residue is directed by flange vapor pressure pump fluid 65 condensed thereon is thus heated to vaporization temperature. These vapors pass through ejector nozzle 68 and this high velocity stream of vapors entrains gases present in the still and forces them through the lower portion of conical element 52 into cup 54 from which they are withdrawn through conduit ll by the backing pump. The pump fluid is condensed on conical element 50 by the action of cool fluid circulated through conduit 52. This condensed pump fluid flows into pump 80 and is forced back into boiler 05 where it is again re-vaporized.

It is preferred that a condensation pump working fluid be selected which has a boiling point, at the pressure in the still, which is to C. below the temperature of the residue oil spread on the surface of boiler 64. The only requisite however is that it be vaporizable at the pressure existing in the boiler and at the temperature of the residue which, of course. varies depending on the material being distilled. Examples of suitable fluids are the phthalic acid esters such as dimethyl, di-butyl etc, phthalates, similar sebacic acid esters, petroleum fractions of low vapor pressure, diphenyl and chlorinated dlph'enyls, etc.

What I claim is:

1. A high vacuum distillation process which comprises in combination subjecting distilland to distillation by introducing it onto the approximate center of a heated rotating surface maintained in a space under high vacuum, causing distilland to flow over the heated surface in a thin film by centrifugal force. condensing vapors thus generated from the distilland, immediately bringing undistilled residue flowing from the periphery of the rotating heated surface into thermal contact with a boiler positioned adjacent the periphery, transferring the heat from the undistilled residue to a low vapor pressure liquid in the boiler, forming. the vapors of the low vapor pressure liquid thus generated into a jet and entraining gases from the space in which the vaporizing surface is positioned in this jet.

2. A high vacuum unobstructed path distillation process which comprises in combination subjecting distilland to distillation by introducing it onto the approximate center of a heated rotating surface maintained in a space under high vacuum, causing distilland to flow over the heated surface in a thin film by centrifugal force, condensing vapors thus generated upon a condensin surface separated from the rotating surface by substantially unobstructed space, immediately bringing undistilled residue flowing from the periphery of the rotating heated surface into thermal contact with a boiler positioned adjacent the periphery of the rotating surface, transferring the heat from the undistilled residue to a low vapor pressure liquid in the boiler forming the vapors of the low vapor pressure liquid thus generated into a jet and entraining gases from the space in which the vaporizing surface is positioned.

3. A high vacuum unobstructed path distillation process which comprises in combination subjecting distilland to distillation by introducing it onto the approximate center of a heated rotating vaporizing surface maintained in a space under high vacuum, causing distilland to flow over the heated surface in a thin film by centrifugal force. condensing vapOrs-thus generated from the distilland upon a condensing surface separated from the rotating surface by substantially unobstructed space, immediately bringing undistilled residue flowing from the periphery of the rotating heated surface into thermal contact with a boiler positioned adjacent the periphery, transferring the heat from the undistilled residue to a liquid in the boiler having a boiling point at the pressure in the distilling space or 20-30 below the temperature of the undistilled residue, forming the vapors of this liquid into a jet and entrainins gases from the space in which the rotating surface is positioned in this jet.

4. A high vacuum distillation process which comprises in combination subjecting distilland to distillation by introducing it onto the approximate center of a heated rotating surface maintained in a space under high vacuum, causing distilland to flow over the heated surface in a thin film by centrifugal force, condensing vapors thus generated from the distilland, immediately bringing the undistilled residue flowing from the periphery of the rotating heated surface into thermal contact with boiler means substantially surrounding the periphery of the rotating surface, transferring the heat from the undistilled residue to a low vapor pressure liquid in the boiler means, forming the vapors of the low vapor pressure liquid thus generated into jet means surrounding the periphery of the rotating surface and entraining gases from the space in which the vaporizing surface is positioned in said jet means.

5. A high vacuum still provided with a rotatable vaporizing surface over which distilland is caused to flow by centrifugal forcecharacterized by a boiler positionedadjacent the periphery of the vaporizing surface, means for directing undistilled hot residue onto the boiler, a low vapor pressure liquid in theboiler, a jet nozzle, means for conveying vapors of low vapor pressure liquid from the boiler to the nozzle, means for entraining gases from the high vacuum still in the jet of vapors issuing from the nozzles, means for condensing the vapor jet and means for returning the condensate to the boiler. I

6. A high vacuum still provided with a rotatable vaporizing surface over which distilland is caused to flow by centrifugal force characterized by a boiler positioned adjacent the periphery of the vaporizing surface, means for directing undistilled hot residue onto the boiler, a liquid in the boiler having a boiling point 20-30 less than the temperature of the hot undistilled residue. a jet nozzle, means for conveying vapors of low vspor pressure'liquld from the boiler to the nozzle, means for entraining gases from the high vacuum still in the jet of vapors issuing from the nozzle, means for condensing the vapor jet and means for returning the condensate to the boiler.

'7. A high vacuum unobstructed path still provided with a rotatable vaporizing surface over which distilland is caused to flow by centrifugal force characterized by boiler means positioned adjacent the periphery said boiler means, a low vapor pressure liquid in the boiler means jet nozzle means attached to said boiler means surrounding the periphery of the vaporizing surface, means for conveying vapors or low vapor pressure liquid from the boiler means to the nozzle means, means for entraining gases from the high vacuum obstructed path still into the vapors issuing from the nozzle means, means for condensing the vapors and means for returning the condensate to the boiler.

- ALBERT C. BOBBIE.

of the vaporizing surface, means for directing undistilled hot residue onto. 

